Python - 找到“深度"递归循环中列表中的元素 [英] Python - Find the "depth" of an element in list in a recursive loop

问题描述

我想使用递归循环(不是函数)知道 Python 列表中元素的深度，但它不起作用.我找到了一些关于函数的答案，但这不是重点.

I want to know the depth of an element in a list in Python using a recursive loop (not a function) but it doesn't work. I find some answers with functions but it's not the point here.

在下面的列表中，像a"是深度 2 和d"是深度 3 之类的东西

Something like 'a' is depth 2 and 'd' is depth 3 in the list below

这是我的代码:

list1 = [['x','y'], ['z','p'], ['m',['a','b','c',['d','e']]]]

level = 0

def print_list(l):
    for e in l:
        global level
        if type(e) == list:
            print_list(e)
            level +=1
        else:
           print(str(e) + ",", str(level))

print_list(list1)

结果:

x, 0
y, 0
z, 1
p, 1
m, 2
a, 2
b, 2
c, 2
d, 2
e, 2

有人有想法吗?

推荐答案

对于此类任务，使用生成器非常方便.它允许您根据需要或作为列表生成值，并使逻辑非常清晰.我从 -1 开始深度，因为我希望第一个嵌套元素处于深度 1(零级将是直接嵌套值，例如 ['a', ['b] 中的 a',...]]:

Using generators is really convenient for this kind of task. It allows you to produce values on demand or as a list and makes the logic very clear. I'm starting the depth at -1 because I want the first nested elements to be at depth 1 (level zero would be immediate nested values like a in ['a', ['b',...]]:

list1 = [['x','y'], ['z','p'], ['m',['a','b','c',['d', 'e']]]]

def levels(l, depth = -1):
    if not isinstance(l, list):
        yield (l, depth)
    else:
        for sublist in l:
            yield from levels(sublist, depth + 1)

list(levels(list1))

结果:

[('x', 1),
 ('y', 1),
 ('z', 1),
 ('p', 1),
 ('m', 1),
 ('a', 2),
 ('b', 2),
 ('c', 2),
 ('d', 3),
 ('e', 3)]

将其制作成字典或使用各种itertools 操纵它.

It would be just as easy to make this a dictionary or use various itertools to manipulate it.

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